Effective Tachyon Dynamics in Superstring Theory

TL;DR

This paper develops a superstring theory-based model for tachyon dynamics on unstable D-branes, capturing stable D-brane properties and spectrum, derived from a boundary-string field theory limit.

Contribution

It introduces a new tachyon dynamics model for superstring theory D-branes, derived from boundary-string field theory in the  limit, capturing stable D-brane features.

Findings

Tachyon potential is positive definite and even in the tachyon field.

Kink solutions replicate properties of stable D-branes.

Spectrum of the kink includes infinite levels starting at zero mass.

Abstract

A recently proposed \ell=\infty field theory model of tachyon dynamics for unstable bosonic D-branes has been shown to arise as the two-derivative truncation of (boundary)-string field theory. Using an \ell\to \infty limit appropriate to stable kinks we obtain a model for the tachyon dynamics on unstable D-branes or D-brane anti-D-brane pairs of superstring theory. The tachyon potential is a positive definite even function of the tachyon, and at the stable global minima there is no on-shell dynamics. The kink solution mimics nicely the properties of stable D-branes: the spectrum of the kink consists of infinite levels starting at zero mass, with spacing double the value of the tachyon mass-squared. It is natural to expect that this model will arise in (boundary) superstring field theory.